Other Events and Attributes:

• Military: Mercenary for King Henry I of England
• Appointments / Titles: Lord
• Appointments / Titles: Sir Knight
• Life Event: Oswestry, Shropshire, England; Chevalier (Knight) breton et baron de Oswerty
• Life Event: Shropshire, England; Sheriff of Shropshire
• Life Event: Dol, Ille-et-Vilaine, Bretagne, France; Steward of Dol
• FSID: K2NQ-X1C
• Religion: Founder of the Sporle Priory
• Life Event: 1086; Witness to Mezuoit Charter in France
• Military: 1097; Took part in the First Crusade

Notes:

After an anonymous work of 1874 drew attention to a strong connection between Alan Fitz Flaad and Brittany, and confirmed Flaad's relationship to Alan the Seneschal, J. Horace Round definitively established and publicized Alan Fitz Flaad's true Breton origins

Alan had two wives, the first one died about 1114 and is not known by name, they had one child together, he then married Avelina before 1126 and had the rest of the children known. Do not merge those wives please. Check sources below.

Alan fitz Flaad was a Breton knight, probably recruited as a mercenary by Henry, son of William the Conqueror, in his conflicts with his brothers. After Henry became King of England, Alan became an assiduous courtier and obtained large estates in Norfolk, Sussex, Shropshire, and elsewhere in the Midlands, including the feudal barony and castle of Oswestry in Shropshire.

Progenitor of Stewart Kings of Scotland and FitzAlan Earls of Arundel

Alan married de Hesdin, Lady Avelina in 1114 in Dol, Ille-et-Vilaine, Bretagne, France. Avelina (daughter of de Hesdin, Sir Ernulf and Baladon, Lady Emmelina) was born in 1088 in Hesdin-l'Abbé, Pas-de-Calais, Nord-Pas-de-Calais, France; died in 1126 in Shrewsbury, Shropshire, England; was buried in 1126 in Paisley Abbey, Renfrewshire, Scotland. [Group Sheet] [Family Chart]

1. FitzAlan, William I was born on 8 Jan 1105 in Shropshire, England; died in 1160 in Oswestry, Shropshire, England; was buried in 1160 in Shrewsbury, Shropshire, England.

Other Events and Attributes:

• FSID: GZXM-WDM
• Occupation: Senescal of Dol

Fledaldus married verch Griffith, Guenta. Guenta (daughter of ap Llywelyn, Gruffydd and of Mercia, Lady Ealdgyth) was born in 1050 in Dol, Ille-et-Vilaine, Bretagne, France; died in 1084 in Wales. [Group Sheet] [Family Chart]

Other Events and Attributes:

• Appointments / Titles: Princess of Wales
• FSID: G8ZS-9TQ

Other Events and Attributes:

• FSID: G8ZS-9T1

Allan married de Lumley, Margaret Filia Rex. Margaret was born in 1030 in Perthshire, Scotland; died on 16 Nov 1093 in Dol, Ille-et-Vilaine, Bretagne, France. [Group Sheet] [Family Chart]

Other Events and Attributes:

• Appointments / Titles: Princess of Scotland
• FSID: G7X9-NSY

Other Events and Attributes:

• Appointments / Titles: King of Gwynedd, Deheubarth, and Powys
• FSID: M1W5-BFF
• Appointments / Titles: Between 1055 and 1063, Wales; High King of Wales

Notes:

Gruffydd ap Llewellyn, King of the Britons
Birth: circa 1007, Rhuddlan, Flintshire, Wales
Immediate Family: son of Llewellyn ap Seisyll and Angharad verch Maredudd, husband of Guerta o Deheubarth and Ealdgyth, father of Nest ferch Gruffydd; Idwal ap Gruffydd; Maredudd ap Gruffydd and Owain Gruffudd, brother of Rhiwallon ap Llewelyn, half brother of Gwenwyn verch Cynfyn; Bleddyn Ap Cynfyn, King of Powys; Rhiwallon ap Cynfyn, Prince of Powys; Angharad verch Cynfyn and Llewelyn ap Cynfyn

Update May 18 2018:
1039-Takes Powys and Gwynedd, kills Iago ap Idwal.
1045-Deheubarth is seized from him by Gruffydd ap Rhydderch who reigns over it for the next ten years.
1055-Gruffydd ap Llywelyn kills Gruffydd ap Rhydderch and regains Deheubarth.
1057-He becomes the first and last prince to unite and rule over all of Wales.
5 Aug 1063-Killed by his own men after his defeat in battle to Harold Godwinson
Per https://en.wikipedia.org/wiki/Gruffydd_ap_Llywelyn His head was sent to Harold, the one who had defeated him. Then Harold married Gruffydd's widow, Ealdgyth, but Harold died 3 years later.

While many different leaders in Wales claimed the title of 'King of Wales', the country was only truly united once: under the rule of Gruffydd ap Llywelyn from 1055 to 1063.

His 1st wife's name in not known, his 2nd wife was Ealdgyth, daughter of Earl Ælfgar of Mercia; the 2 women should not be confused OR MERGED!

Gruffydd married of Mercia, Lady Ealdgyth in 1054 in Rhuddlan, Flintshire, Wales. Ealdgyth (daughter of of Mercia, Ælfgar and Mallet, Ælfgifu) was born in 1040 in Kingdom of Mercia, England; died in 1066 in Chester, Cheshire, England; was buried in 1066 in Spalding, Lincolnshire, England. [Group Sheet] [Family Chart]

Other Events and Attributes:

• FSID: 9CW5-JNL
• Appointments / Titles: 1054; Queen Consort of England; Queen Consort of Wales

Notes:

05 Aug 1063 in Snowdonia, Wales; After escaping a surprise attack by the forces of Harold Godwinson in 1062, Gruffydd lost his head to Harold's brother in Snowdonia on 5 August 1063.

Jan 1066 in London, England; Ealdgyth married for a 2nd time to Harold Godwinson (King of England). The marriage was likely politically motivated and is believed to have occurred shortly before or after he became king in January 1066.

14 Oct 1066 in Hastings, Sussex, England; Ealdgyth's second husband, King Harold Godwinson, died on 14 October 1066 in the Battle of Hastings against William the Conqueror

14 Oct 1066 in Cheshire, England; At the news of Harold's death, Ealdgyth's brothers went to London to fetch her and immediately sent her to Chester for shelter. It is unknown what happened to her thereafter.

NOT THE SAME AS EDITH SWANNECK: Ealdgyth was the wife of Gruffudd ap Llywelyn and 2nd wife of Harold Godwinson, while Edith Swanneck was the mistress/consort of Harold Godwinson BEFORE his marriage to Ealdgyth

1041 Capture of Wife of Hywel
Some historians hold that Gruffydd had a liaison with the wife of Hywel ab Edwin, taken as part of "the spoils of war" in 1041.
Wolcott states that in 1041 that during a battle with King Hywel ap Edwin of Deheubarth, Gruffudd ap Llewelyn seized Hywel's wife. The 3 principal versions of the Brut differ as to what Gruffudd had in mind when he took the lady.
- Took her for his own, i.e. took her for a mistress;
- Took her as his own wife
- Took her and controlled her. This version might describe his simply taking the lady hostage, a common occurrence in warfare during that era. Since we believe he already had a wife, and knew the lady was a daughter of Earl Leofric we suspect she was taken as a bargaining chip in the event Mercia interfered with his plans to take Deheubarth and, indeed, all of Wales.

Edith or Ealdgyth, was the daughter of Aelfgar, who became Earl of East Anglia in 1053 and Earl of Mercia in 1057, dying shortly after 1062.
Wolcott emphasizes that while many suppose that Aeldgyth was the same lady Gruffudd had taken from Hywel in 1041, the chronology does not fit. The lady widowed in 1063 bore 2 sons to Harold before 1066, but the lady taken from Hywel would have been in her mid or late 40's by then.
First Marriage to Gruffudd
Gruffudd married, first, about 1057, as her first husband, Edith (or Ealdgyth Ealgyth Aldgyth), daughter of Aelfgar (of Elgar), King of Mercia, son of Leofric, son of Leofwine, the earl of Mercia who died before 1032. Her grandmother was Lady Godiva.
Edith married, about 1057, Gruffudd ap Llywelyn.

After his first wife Nest died, probably in childbirth, Gruffudd married Ealdgyth about 1055 . The marriage of Gruffudd and Eadgyth would have been about 1055 when Gruffudd and Aelfgar were known to be allies.
The number of Ealdgyth's children with Gruffydd is also in some dispute. While Nesta is her daughter, there is some uncertainty about the mother of Maredudd and Idwal.
m.1(c. 1050 or 1056/7) Gruffydd ap Llywelyn of Wales (d. 1063).[2] Issue: 1 proven:

(unproven) Maredudd "Meredith" ap Gruffydd (d. 1068 or later; or 1070).
(unproven) Idwal ap Gruffydd (d. 1068 or 1070).
Nesta.
m. Osbern FitzRichard
Per https://www.geni.com/people/Ealdgyth/6000000000115658521, Ealdgyth was butied in Spalding, Lincoln, England

Other Events and Attributes:

• FSID: GQWS-BS4

Flaad married Deatholl, Muldivana. Muldivana was born in UNKNOWN in Perth, Perthshire, Scotland; died in 1020 in Dol, Ille-et-Vilaine, Bretagne, France. [Group Sheet] [Family Chart]

Other Events and Attributes:

• FSID: GQWS-RR5

Other Events and Attributes:

• Appointments / Titles: King of Gwynedd, Powys and Deheubarth
• Appointments / Titles: King of Wales
• FSID: 9376-JCH
• Appointments / Titles: 1018, Wales; King of Gwynedd and Powlys

Notes:

Llywelyn ap Seisyll (died 1023) was an 11th-century King of Gwynedd, Powys and Deheubarth.

Llywelyn was the son of Seisyll, a man of whom little is known. Llewelyn first appears on record in 1018, that year he defeated and killed Aeddan ap Blegywryd along with four of his sons and obtained Gwynedd and Powys.

In 1022, a man named Rhain the Irishman was made king of Deheubarth, he claimed to be a son of Maredudd ab Owain, whose daughter Angharad had married Llywelyn. Llywelyn made war against Rhain, they fought a battle at Abergwili, and after a “slaughter on both sides” Rhain was killed allowing Llywelyn take control of Deheubarth.

Llywelyn, after his success against Rhain, died in 1023. The Brut y Tywysogion portrays Llywelyn’s reign as one of prosperity saying “complete in abundance of wealth and inhabitants; so that it was supposed there was neither poor nor destitute in all his territories, nor an empty hamlet, nor any deficiency.” Llywelyn was called "King of the Britons" by the Annals of Ulster.

Llywelyn had one son called Gruffydd; he did not succeed his father, possibly because he was too young to do so. Gruffydd went on to become the first and only true King of Wales (the only one to rule over all the territory), however he was killed by his own men in 1063. Gruffydd’s own sons Maredudd and Idwal died in 1069, fighting at the Battle of Mechain.

As Llewelyn's grandfather is not known some scholars have said it was a man named Ednowain or Owain others Rhodri. Yet a more likely proposition is that Llewelyn was a nephew to King Cadell ap Brochwel of Powys, son of his younger brother Seisyll and that he did not acquire Powys by conquest but hereditary right and then conquered Gwynedd from Aeddan son of Blegywryd.

Llewelyn married verch Maredudd, Queen Angharad in 994. Angharad (daughter of ap Owain, King Maredudd and verch Hywel Dda, Lady Angharad) was born in 980 in Dynefwr Castle, Llandeilo, Carmarthenshire, Wales; died on 8 May 1058 in Powis Castle, Montgomeryshire, Wales; was buried in 1077 in Wales. [Group Sheet] [Family Chart]

Other Events and Attributes:

• Appointments / Titles: Queen of Deheubarth
• Appointments / Titles: Queen of Gwynedd
• Appointments / Titles: Queen of Powys
• FSID: 9HVH-9GD

Notes:

Biography
Angharad verch Maredydd Queen of Powys was born in about 0982

Parents
Angharad's father was Maredydd ap Owain, son of Owain ap Hywel and Angharad verch Llewelyn.

994 First Marriage to Llywelyn ap Seisyll
In 994 Angharad married Llywelyn ap Seisyll.

The marriage of Angharad and Llywelyn is confirmed by the Chronicle of the Princes of Wales which records that "Bleddyn son of Cynvyn and Gruffudd son of Llywelyn were brothers by the same mother Angharad daughter of Meredudd king of the Britons".

Llywelyn was aged 14 at the time (so born in 980). The Gwentian Chronicle records that "Llywelyn son of Seisyllt lord of Maes Essyllt although but a youth not more than fourteen years of age" married "Yngharad, daughter of Meredydd on of Owain" in 994

1023 Anghard's Second Marriage to Cynfyn ap Gwerstan
As the widow of Llywelyn, Angharad married secondly in 1023 Cynfyn ap Gwerstan, King of Powys, son of Gwerstan.

Death
She died in Wales in 1077 (83-91)

Issue
Angharad had children by two marriages. Her second husband Cynfyn likely had children by a previous wife, and these children are sometimes mis-attributed to Angharad.

1.) Gruffydd ap Llewelyn, son of Angharad and her first husband Llewelyn. Gruffydd, king of Gwynedd & Powys was born about 1011 in Rhuddlan, Flintshire, Wales and died 5 August 1063. He was the child of Llywelyn ap Seisyllt and Angharad verch Maredudd. Gruffydd did not succeed his father, possibly because he was too young to do so when his father died in 1023. Gruffydd went on to become the first King of Wales, however he was killed by his own men in 1063. Gruffydd's own sons Maredudd and Idwal died in 1069, fighting at the Battle of Mechain. Gruffydd ap Llywelyn inflicted a series of defeats on the English, and made alliances with the enemies of King Edward the Confessor. Gruffydd fought a long campaign against rival kings to win overall control of Wales. By 1055, he had become master of Deheubarth and had expanded his rule to the lesser kingdoms of Morgannwg (Glamorgan) and Gwent. In 1063, Earl Harold Godwinsson (later Harold II) and his brother Tostig made a joint attack on Gwynedd. At the same time, Deheubarth rebelled against Gruffydd's rule. Gruffydd fled and was murdered by his own men. Gruffydd married Ealdgyth, a daughter of Ælfgar, Earl of Mercia. Ealdgyth married second in circa 1064 to Harold Godwinson, the last Anglo-Saxon King of England. Ealdgyth and Gruffydd had a son: Maredudd ap Gruffydd who was excluded from the throne by his uncles Bleddyn ap Cynfyn and Rhywallon ap Cynfyn. Gruffydd ap Llewelyn, king of the Britons

2.) Rhiwallon ap Cynfyn ap Gwerystan, son of Angharad and Cynfyn, born c. 1024, was elevated to king of Powys after the death of Gruffudd ap Llewelyn Rhiwallon was killed in the Battle of Mechain, about 1068. This is the most concrete date associated with Rhiwallon. Warriors were generally young men, though the princes for whom they fought were often older and also expected to fight. Estimate that Rhiwallon was aged 45 at Mechain, and his birth year would be, say, 1025, or if the first born of his mother's second marriage, 1024. Florence of Worcester records that he was appointed King of Powys by King Edward "the Confessor" after the defeat of Gruffydd. The Chronicle of the Princes of Wales records in 1106 that "Bleddyn and Rhiwallon, sons of Cynvyn, were brothers, from Angharad daughter of king Maredudd". Florence of Worcester records that he was appointed King of Powys by King Edward "the Confessor" after the defeat of Gruffydd. The Chronicle of the Princes of Wales records that "the action of Mechain took place between Bleddyn and Rhiwallon, sons of Cynvyn, Maredudd and Ithel, sons of Gruffudd" in 1068, adding that "Ithel was killed in the battle and Maredudd died of cold in his flight, and Rhiwallon son of Cynvyn was slain". The name of Rhiwallon´s wife is not known.

3.) Bleddyn ap Cynfyn, born c. 1025, who was made king of Gwynedd after Gruffudd's death in 1063, and additionally king of Powys when Rhiwallon was killed in 1069 Bleddyn ap Cynfyn of Deheubarth was born in 1025 and died in 1075. Bleddyn ap Cynfyn born about 1025 Montgomeryshire, Bleddyn ap Cynfyn was the son of Princess Angharad ferch Maredudd (of the Dinefwr dynasty of Deheubarth) and her second husband Cynfyn ap Gwerstan, The Chronicle of the Princes of Wales records in 1106 that "Bleddyn and Rhiwallon, sons of Cynvyn, were brothers, from Angharad daughter of king Maredudd". He succeeded his uterine half-brother in 1063 as King of Gwynedd and Powys. He married secondly m. Haer ferch Gillin, and thirdly a daughter of Brochwel

4.) Gwerfyl, born c. 1026, who married Gwrgan ap Ithel Ddu of Glamorgan, and was mother to Iestyn ap Gwrgan. Without naming her, Boyer, following Bartrum, notes a daughter of Cynfyn who married Gwrgan ab Ithel ab Idwallon ap Morgan Mawr (who was King of Morgannwg).

Other Events and Attributes:

• FSID: LZ8J-9XT
• Appointments / Titles: Between 1051 and 1052, East Anglia, Norfolk, England; Earl of East Anglia
• Appointments / Titles: Apr 1053, Kingdom of Wessex (England); Earl

Notes:

Ælfgar (died c. 1060) was the son of Leofric, Earl of Mercia, by his famous mother Godgifu (Lady Godiva). He succeeded to his father's title and responsibilities on the latter's death in 1057. He gained the additional title of Earl of East Anglia, but also was exiled for a time.

Ælfgar married Aelfgify, sister of William Malet, Lord of Eye.
They had 4 children:
- Burgheard, died returning from Rome 1060, buried at Reims
- Edwin, Earl of Mercia
- Morcar, Earl of Northumbria
- Ealdgyth, married (1st) Gruffydd ap Llywelyn, King of Wales (2nd) Harold Godwinson, King of England.
--------------------------------------------------------------
from www.geni.com

Ælfgar
Also Known As: "Algar III Earl of Mercia", "Aelfgar", "Alfagar of Mercia"
Birthdate: circa 1002 (57)
Birthplace: Mercia, England
Death: between 1059 and 1063 (53-65)
Mercia, England
Place of Burial: Coventry, Warwickshire, England
Immediate Family:
Son of Leofric III, earl of Mercia and Lady Godiva
Husband of Ælfgifu
Father of Ealdgyth; Eadwyne, Duke of Mercia; Morcar, Earl of Northumbria and Burgheard
Occupation: Earl of East Anglia and Mercia, Earl of Mercia, King of Mercia

Aelfgar, Earl (d 1062), was the son of Leofric of Mercia and his wife Godgifu, the 'Lady Godiva' of legend. Bitter jealousy existed between the ancient Mercian house and the new and successful family of Godwine. When, in 1051, Godwine and his sons gathered their forces against the king and his foreign favourites, Aelfgar and Leofric were among the party which stood by Eadward at Gloucester, and on the outlawry of Harold his earldom of East Anglia was given to Aelfgar. The new earl ruled well, and the next year, on the restoration of Godwine's house, cheerfully surrendered the government to Harold. On the death of Godwine in 1053, the West Saxon earldom was given to Harold, and East Anglia was again committed to Aelfgar. In 1055, at the Witenagemont held in London, Aelfgar was accused of treason, and was outlawed 'for little or no fault at all,' according to all the Chronicle writers, save one. The Canterbury writer, however, who was a strong partisan of Harold, says that Aelfgar owned his guilt, though he did so unawares. He fled to Ireland and engaged eighteen ships of the Northmen. He crossed to Wales and made alliance with Gruffydd of North Wales. With Gruffydd and a large host of Welshmen, Aelfgar and his Norse mercenaries invaded Herefordshire. Ralph, the king's nephew, the earl of the shire, met the invaders with an army composed both of Frenchmen and English. He foolishly compelled his English force to go to battle on horseback, contrary to their custom. He and his Frenchmen fled first, and the battle was lost. Aelfgar and his allies entered Hereford. They sacked and burnt the minster and the city, slaying some and taking many captive. To check this invasion the whole force of the kingdom was gathered under Earl Harold and Aelfgar and his allies were chased into South Wales. In 1055 Aelfgar made peace with Harold, was reconciled to the king and restored to his earldom. On the death of Leofric, in 1057, Aelfgar received his father's earldom of Mercia. The position of his new earldom as regards Wales and Ireland encouraged his restlessness, and the weakness and instability of King Eadward the Confessor made rebellion no serious matter. It was probably while the only force capable of maintaining order in the kingdom was removed by the pilgrimage of Harold, that Aelfgar was, in 1058, outlawed for the second time. His old allies were ready to help him. Gruffydd and a fleet of the Northmen, which seems to have been cruising about on the look-out for employment, enabled him to set his outlawry at defiance and to retain his earldom with the strong hand. IN one good deed Aelfgar and Harold acted together. On the surrender of the see of Worcester by Archbishop Aldred in 1062, both the earls joined in recommending Wulfstan for the bishopric. Soon afterwards, probably in the same year, Aelfgar died. His wife's name was Aelfigifu. He left two sons, Eadwine and Morkere, who played a conspicuous part in English history. A charter of the abbey of ST Remigius at Rheims records that Aelfgar gave Lapley to that house for the good of the soul of a son of his named Burchard, who was buried there. His daughter, Aldgyth, married her father's ally Gruffydd, and, after the deaths of Aelfgar and Gruffydd, married as her second husband Harold, her father's old enemy. [Dictionary of National Biography I:148-149]

Aelfgar, of age 1051, d. shortly after 1062, Earl of East Anglia 1053, Earl of Mercia 1057, banished 1058; m. Aelfgifu, by whom 3 known sons: Eadwine, Morkere, and Burchard, whose issue are unknown, and a daughter Aldgyth [as well as Edith or Aldgyth]. [Ancestral Roots, Line 176a-3]

______________________________

Earl of East Anglia 1053; Earl of Mercia 1057.

From Gen-Med Archives, June 19, 1999; author: Leo van de Pas:

"In 1055, he was forced to seek the protection of Gruffyd in Wales, in that year Gruffyd and Alfgar burned down St.Aethelbert's minster and all the town of Hereford. In 1058 Alfgar, without having given reason, was outlawed, and went to Ireland and Wales where he got himself a great band and then travelled to Hereford. After a violent battle Alfgar was reinstated and given back all that had earlier been taken from him."

Bet. 1051-1052 in East Anglia, Norfolk, England; When the Godwins were exiled from England in 1051 Ælfgar was given the Earldom of East Anglia, which had been that of Harold Godwinson. When Harold returned in 1052, the property was restored to him..

Apr 1053; Harold became Earl of Wessex after his fathers death April 1053, and the earldom of East Anglia returned to Ælfgar.

1058; Ælfgar was exiled by King Edward in 1055 but was reinstated later the same year.

Ælfgar married Mallet, ÆlfgifuEngland. Ælfgifu (daughter of of Northumbria, Morcar and of Northumbria, Ealdgyth) was born in 997 in Kingdom of Wessex (England); died in 1092 in Kingdom of Mercia, England; was buried in 1092 in Coventry, Warwickshire, England. [Group Sheet] [Family Chart]

Other Events and Attributes:

• FSID: M47Y-DXN

Notes:

Aelfgifu was the wife of Aelfgar the Earl of Mercia. They had 4 children:
- Burgheard, died returning from Rome 1060, buried at Reims
- Edwin, Earl of Mercia
- Morcar, Earl of Northumbria
- Ealdgyth, married (1st) Gruffydd ap Llywelyn, King of Wales (2nd) Harold Godwinson, King of England.

Aelfgifu is believed to be the sister of William Malet, Lord of Eye.
Not much is know about the wife of Aelfgar, Earl of Mercia. Most sources do not name her at all, others claim her name was of Aelgifu. Some people try to make her Ælfgifu, the daughter of King Æthelred the Unready, however, this is not possible. Ælfgifu, the daughter of King Æthelred, is well known to have married Uchtred of Bamburgh about 1014. Uchtred died in 1016 and not much is known about Ælfgifu after that, which leads many to presume she remarried to Ælfgar. There are records documenting the remarriage of Uchtred's other wives but there is nothing documenting Ælfgifu's marriage to Aelfgar. As the daughter of King Æthelred she whould have been much more high profile than Uchtred's other wives and yet nothing. Surely if Aelfgar had married the daughter of a king it would be documented and he would have used those familial relations to his advantage. Ælfgifu did have a daughter named Ealdgyth, just like Aelfgar and his wife, however, the father of her daughter is known to be Uchtred. Ealdgyth, Uchtred's daughter was born between 1014 and 1016 and is known to have married Maldred, Lord of Allerdale about 1036, together they had 3 children. The daughter of Aelfgar, born 1026 or much later, would have been too young to have married Maldred in 1036. She is known to have married Gruffydd ap Llywelyn, King of Wales about 1055 and had at least one child. After his death she married Harold Godwinson, King of England in 1066 and had a son. The daughter of Uchtred born no later than 1016 would have been at least 50 years old in 1066 and past child bearing years. The daughter of Uchtred can not possibly be the same woman that was also the daughter (or step-daughter) of Aelfgar. And Ælfgifu the wife of Uchtred was not also the woman who married Aelfgar. Additionally, William Malet, High Sheriff of Yorkshire, Norfolk, and Suffolk, is "said to be the brother of Aelgifu, wife of Ælfgar, Earl of Mercia". Malet was certainly not the son of King Æthelred.

In a one on one comparison, it can be seen they are not the same woman:
Ælfgifu: Born: 991 to 1001
Father: King Æthelred
Marriage: Uchtred 1014
Daughter: Ealdgyth, born 1014 to 1016

Aelgifu: Born: ?
Father: ? same father as William Malet
Marriage: Aelfgar about 1023
Daughter: Ealdgyth, born sometime after 1025

Some records such as The Foundation for Medieval Genealogy
report Aelgifu's parents as Morcar Thegn of Derbyshire and his wife Ealdgyth. However, this does not appear to fit with her also being the sister of William Malet. UNLESS they were half-siblings sharing the same mother but not the same father. FMG does not have any records supporting this parent/child relationship. Aelgifu did name 2 of her children Morcar and Ealdgyth, these names are not seen in Aelfgar's family so the children could well be named in honor of Aelgifu's parents. This is just a possibility however with out sources to confirm it.
http://fmg.ac/Projects/MedLands/ENGLAND,%20AngloSaxon%20nobility.htm#AelfgifuNorthumbriaMAelfgarMercia